In 2006, signing Ben Wallace to a deal would have been in an incredible franchise-changing move to radically alter the outlook of your defense.

In 2009, trading for him would have been seen as a desperate and flawed move towards overpaying for an unproductive and underwhelming player.

In 2012, it’s a pretty solid move which can shore up your bench, bring veteran leadership (VETERAN LEADERSHIP ALERT) to your locker room and provide you with a strong-willed icon to rally behind.

In 2007, Marcus Camby was a shot-blocking machine, the Defensive Player of the Year, an All-Star candidate and considered a superb all-around player.

In 2010, Camby was considered an overrated defender who helped too much, gave up too many points at the rim, and relied too much on his shot-blocking to be considered actually that good of a defender.

In 2012, he’s a solid addition and a huge upgrade to the Knicks’ bench, bringing the kind of tough defense at the rim and rebounding they’ve been missing for several years down low. He and Tyson Chandler should prove to be quite the conundrum for teams.

And so it goes. People like to blame the 24-second news-cycle for the way we tend to lose perspective on things, but it’s always been this way. Go back through the articles all the way back to the SI.com archive about anyone whose game went up or down, and you’re going to find things which look ridiculous in hindsight. That’s pretty standard. You write what you know at the time and some things in this world are just unforeseeable. Look at Stephon Marbury’s career and tell me if during it you would have thought he’d wind up eating Vaseline on UStream. It happens all the time. But particularly with big men defenders, we see a different loping arc.

Tyson Chandler was once thought of as just an athlete who couldn’t put it together. Then all of a sudden in New Orleans, he put it together, and while dunking CP3 alley-oops, it turned out he was a pretty great defender. Three years later, he wins a title with the Mavericks as the biggest difference-maker on a team that had been great for a decade.

Wallace was such a pivotal part of the Pistons’ championship, it’s almost impossible to overrate his performance. He was everywhere. Then in Chicago, he was slow-footed, slow-healing, and just slow. Scott Skiles’ decision in 2008 to repeatedly play him over Joakim Noah was the stuff to drive your hair out. But then he returned to Detroit after a sting with Cleveland where he was just dead money, and he was that lovable veteran who handled the defense as well as he could with the team falling apart around him. The Pistons have moved on this season, after it was thought Wallace would retire, but he’s reportedly thinking about giving it another go. He was still productive last season, still a good defender, but the expectations have changed. That’s the big differential.

It’s the same with Camby. There was a huge backlash against Camby right before he was traded to the Clippers from Denver, based on his tendency to pursue the block instead of keeping with the smart rotation. But since then, he’s been a good defender in Los Angeles, a great defender in Portland, and a pretty good one in Houston. He re-joins the Knicks and should make a substantial impact… for a guy his age. The expectation has changed, and that allows us to view him either more accurately or more favorably, depending on your inclination.

It makes you wonder about the future of so many players we routinely flambe on the internet stove. JaVale McGee could change his identity defensively four times over the next eight years of his career. Joakim Noah could reach DPOY status and then plummet to overrated, injury-prone joke-butt before finishing his career in Chicago a hero. Serge Ibaka laughably wound up second in Defensive Player of the Year votes last year, largely based on the same reasoning Camby wound up winning it in 2007. But he’s going to improve, just like Chandler and Camby did. What then?

The point, as always, is that an NBA career is almost never the same year-in-and-year out. It’s a topographical map with texture, peaks and valleys. Defensive big men are more prone to latter development we’re discovering, because of the amount of mental improvement and wisdom needed to excel in the NBAs new “all-help-all-the-time” defensive structure. You can label a player fairly as a poor defender now, but don’t let it sink in so much that you forget to watch their improvement, even as they get older. Point guards must improve younger, big men almost always make a jump later in their careers. And their continuing evolution makes up a significant impact on how team defenses, and legacies, can change.

Ben Wallace the leader, Camby the rock, Chandler the icon. What will McGee, DeAndre Jordan, and Ibaka become, before they become what they will even later?